A good alignment of the teeth creates a favorable impression on the social life and makes an excellent force of mastication from a point of medical view. Consequently, a lot of people have an orthodontic treatment in recent years. In particular, a force of mastication has been reduced for modern people in accordance with a variation of a food culture. Therefore, a space for growing the teeth in a mouth of modern people has a tendency to be decreased, and an alignment of the teeth has a tendency to be degraded for modern people in the case in which an orthodontic treatment is not carried out.
Based on the above tendency, an orthodontic treatment is carried out in a childhood when permanent teeth are grown in many cases.
For an orthodontic treatment in general, an orientation of a tooth is tried to be modified by a series of operations described in the following as disclosed in Japanese Patent Application Laid-Open Publication No. 2001-161716 for instance (see FIG. 10 and FIG. 11 herein).
(1) An orthodontic bracket 143 is bonded to a surface 141A of a plurality of teeth.
(2) An arch wire 146 is fitted by insertion to a depressed part 145 that has been formed in the bracket 143, and the arch wire 146 is disposed across between the brackets 143.
(3) An elastic force of the arch wire 146 is applied to the teeth.
Such an orthodontic bracket 143 has been made of a metal. Consequently, the orthodontic bracket 143 is not so aesthetic due to a difference between the color tones of a tooth and a metal bracket. In order to improve the problem point, a transparent plastic or a plastic that is tinctured to be a color similar to a color tone of a tooth is used as a constitutional material of the orthodontic bracket 143.
However, the orthodontic bracket and the arch wire are engaged with each other only by fitting the arch wire by insertion to the depressed part 145 that has been formed in the orthodontic bracket. Consequently, in order to fit the arch wire to the orthodontic bracket that is disposed at the end part, it has been general that the orthodontic bracket that is disposed at the end part and the arch wire are tied up by using a wire 150 for a ligation. In addition, since the arch wire 146 is fitted by insertion to the depressed part 145 that has been formed in the bracket 143, there is no problem in the case in which an orthodontic treatment is carried out by pressing a tooth. However, in the case in which a tooth that is recessed is pulled to a front in an orthodontic treatment, the arch wire 146 is broken out of the depressed part 145 that has been formed in the bracket 143 in some cases. Even in such a case, it is necessary that the arch wire 146 is tied up to the bracket 143 by using the wire 150 for a ligation.
Since it is necessary that the arch wire is tied up for the conventional orthodontic bracket as described above, the form of the conventional orthodontic bracket is complicated. Moreover, in the case in which a ligation is carried out, a tooth is prevented from being moved due to a ligation force in some cases. Moreover, the ligation operation is carried out by a hand work, and requires a high level of proficiency.
In the case in which a surface state and a shape of the orthodontic bracket becomes more complicated, food particles and debris remain in a gap that is formed by the orthodontic bracket, the arch wire, or the wire for a ligation in some cases. Such food particles and debris may cause a formation of the tooth decay in some cases.
An orthodontic treatment is carried out to improve a sensuousness of the teeth. In order to prevent the tooth decay in accordance with the above described orthodontic treatment from occurring and in consideration of an aesthetic property of the bracket and an operational property of a ligation, Japanese Patent Application Laid-Open Publication No. 2007-105361 (JP '361) discloses an invention of an orthodontic bracket in which a slot hole 252 that penetrates in a horizontal direction is formed in a base part 255 that is fixed on the surface of the teeth as shown in FIG. 12 herein. JP '361 discloses that the slot hole 252 is formed in such a manner that a penetrating direction of the slot hole 252 is different from a forming direction of the base part 255 and is inclined to the forming direction of the base part 255 in order to change an orthodontic treatment direction in accordance with each of the teeth as shown in FIG. 13. As described above, by displacing and inclining the slot hole 252 from the forming direction of the base part 255, a wiring direction of the arch wire is not linear, and a torque occurs by curving a wiring direction of the arch wire, thereby carrying out an orthodontic treatment of an angulation (an outward inclination) of the teeth.
However, there is one displaced slot hole 252 that is disclosed in JP '361. It is necessary that a torque for carrying out an orthodontic treatment of an outward inclination of the teeth depends on a torque that is caused by the elasticity of one arch wire that has been inserted into the slot hole 252. It is necessary that an arrangement of the entire teeth is corrected in a balanced manner for an orthodontic treatment. In the case in which a high torque is tried to be obtained in order to carry out an orthodontic treatment of an outward inclination of a part of the teeth, an extra stress is applied to other teeth.
The orthodontic bracket that is disclosed in JP '361 has a property in which food particles and debris are less likely to remain since a side surface of the orthodontic bracket is inclined. However, it is general that an adhesive agent is applied to the rear face of the orthodontic bracket above described, the side surface of the orthodontic bracket is picked up with tweezers, and the orthodontic bracket is mounted on the surface of the teeth. In the case in which the entire side surface is inclined as disclosed in JP '361 in the concrete, it is hard to pick up the orthodontic bracket with tweezers. Consequently, it is difficult that the orthodontic bracket that is disclosed in JP '361 is mounted on the surface of the teeth in an accurate fashion unfortunately.